1. Field of the Invention
The present invention relates generally to air filters and, more specifically, to a washable frameless electrostatic air filter for use in ventilation systems of heating and air conditioning units in homes and businesses.
2. Description of the Related Art
Electrostatic air filters have been known in the art for many years. Some of these air filters have configurations in which the filtering media accumulates a charge by virtue of air passing through that media. Other types of electrostatic air filters use some type of high-voltage source electrically connected to the filter media, and/or a similar high-voltage source electrically connected to an electrode which is used to ionize particles in the air that are then collected by a filter media. These types of air filters are efficient in removing pollutants from the air and help keep clean the ventilation systems on heating and air conditioning units.
However, prior electrostatic air filters have had some disadvantages. One major problem is noise that is generated by metal and plastic frames on the air filters when heating or air conditioning units turn on or off. Often when the units are just running the air filters vibrate in the filter receptacle and make noise. Another common problem is the inability of air filters to seat and seal tight to the inside lip of filter receptacles. This allows dirty air to go around the air filter frame without being filtered, thus, lowering the cleaning capabilities of the air filter. Thus, there is a need for an improved electrostatic air filter which does not have these problems.
U.S. Pat. No. 3,768,642, issued on Oct. 30, 1973 to Elwood F. Hansen et al., describes a shipping and dispensing carton for a stack of compressed and bound resilient, compressible frameless air filter elements. Hansen et al. '642 do not suggest the frameless electrostatic air filter configuration according to the claimed invention.
U.S. Pat. No. 3,877,909, issued on Apr. 15, 1975 to Elwood F. Hansen, describes an internally supported, composite frameless filter. Hansen '909 does not suggest the frameless electrostatic air filter configuration according to the claimed invention.
U.S. Pat. No. 4,902,306, issued on Feb. 20, 1990 to Gilbert W. Burnett et al., describes a dual-dipole electrostatic air filter. Burnett et al. do not suggest the frameless electrostatic air filter configuration according to the claimed invention.
U.S. Pat. No. 5,330,559, issued on Jul. 19, 1994 to William A. Cheney et al., describes an electrostatic air cleaner. Cheney et al. '559 do not suggest the frameless electrostatic air filter configuration according to the claimed invention.
U.S. Pat. No. 5,336,299, issued on Aug. 9, 1994 to Gary L. Savell, describes a multi-layered electrostatic air filter. Savell does not suggest the frameless electrostatic air filter configuration according to the claimed invention.
U.S. Pat. No. 5,403,482, issued on Apr. 4, 1995 to William C. Steere et al., describes a coreless filter. Steere et al. do not suggest the frameless electrostatic air filter configuration according to the claimed invention.
U.S. Pat. No. 5,474,599, issued on Dec. 12, 1995 to William A. Cheney et al., describes an electrostatic air cleaner. Cheney et al. '599 do not suggest the frameless electrostatic air filter configuration according to the claimed invention.
U.S. Pat. No. 5,509,950, issued on Apr. 23, 1996 to Peter van de Graaf et al., describes a filter device including a filter element having a filter medium arranged in zig-zag shaped pleats. Van de Graaf et al. do not suggest the frameless electrostatic air filter according to the claimed invention.
U.S. Pat. No. 5,597,645, issued on Jan. 28, 1997 to Richard D. Pike et al., describes a nonwoven web of filter media for gaseous fluids. Pike et al. do not suggest the frameless electrostatic air filter configuration according to the claimed invention.
U.S. Pat. No. 5,616,169, issued on Apr. 1, 1997 to Ernest de Ruiter et al., describes a seal-free and frame-free odor and/or pollutant filter. De Ruiter et al. do not suggest the frameless electrostatic air filter configuration according to the claimed invention.
U.S. Pat. No. 5,618,324, issued on Apr. 8, 1997 to Bruno Sommer et al., describes a filter insert for a vehicle air conditioning system. Sommer et al. do not suggest the frameless electrostatic air filter configuration according to the claimed invention.
France Patent document number 2,354,125, published on Feb. 10, 1978, describes an air filter with a pleated cartridge filter. France '125 does not suggest the frameless electrostatic air filter configuration according to the claimed invention.
German Patent document number 1,203,936, published on Oct. 28, 1965, describes an exchangeable air filter. German '936 does not suggest the frameless electrostatic air filter configuration according to the claimed invention.
Great Britain Patent document number 2,204,810 A, published on Nov. 23, 1988, describes an air filter including two layers of resilient foamed polypropylene. Great Britain '810 does not suggest the frameless electrostatic air filter configuration according to the claimed invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.